Experimental and Numerical Studies on the Effect of Lithium-Ion Batteries� Shape and Chemistry on Heat Generation

Abstract

Data sets of internal resistances and open-circuit voltage of a particular battery are needed in ANSYS Fluent program to predict the heat generation accurately. However one set of available data called Chen抯 original does not cover all types and shapes of batteries. Therefore this research was intended to study the effects of shapes and polarization chemistries on heat generation in Li-ion batteries. Two kinds of material chemistries (nickel manganese cobalt oxide NMC and lithium iron phosphate LFP) and three forms (cylindrical pouch and prismatic) were studied and validated with the experiment. Internal resistance was unique to each cell battery. Differences in shapes affected the magnitude of internal resistance affecting the amount of heat generation. Pouch and prismatic cells had lower internal resistance than cylindrical cells. This may be the result of the forming pattern in which the anode cathode and separator are rolled up making electrons difficult to move. In contrast the pouch and prismatic cells are formed as sandwich layers resulting in electrons moving easily and lowering the internal resistance. The shapes and chemistries did not impact the entropy change. All batteries displayed exothermic behavior during a lower SOC that gradually became endothermic behavior at around 0.4 SOC onwards. ? 2022 by the authors.